CVE-2022-49554

In the Linux kernel, the following vulnerability has been resolved: zsmalloc: fix races between asynchronous zspage free and page migration The asynchronous zspage free worker tries to lock a zspage's entire page list without defending against page migration. Since pages which haven't yet been locked can concurrently migrate off the zspage page list while lock_zspage() churns away, lock_zspage() can suffer from a few different lethal races. It can lock a page which no longer belongs to the zspage and unsafely dereference page_private(), it can unsafely dereference a torn pointer to the next page (since there's a data race), and it can observe a spurious NULL pointer to the next page and thus not lock all of the zspage's pages (since a single page migration will reconstruct the entire page list, and create_page_chain() unconditionally zeroes out each list pointer in the process). Fix the races by using migrate_read_lock() in lock_zspage() to synchronize with page migration.

• linux linux kernel (>= 4.14 < 4.14.282) • linux linux kernel (>= 4.15 < 4.19.246) • linux linux kernel (>= 4.20 < 5.4.197) • linux linux kernel (>= 5.5 < 5.10.120) • linux linux kernel (>= 5.11 < 5.15.45) • linux linux kernel (>= 5.16 < 5.17.13) • linux linux kernel (>= 5.18 < 5.18.2)